WAVES OF TOPOLOGICAL ORIGIN IN THE FLUID EARTH SYSTEM AND BEYOND

Symmetries and topology are central to our understanding of physical
systems. Topology, for instance, explains the precise quantization of the Hall
effect and the protection of surface states in topological insulators against
scattering from disorder or bumps. However, discrete symmetries and
topology have not, until recently, contributed much to our understanding of
the fluid dynamics of oceans and atmospheres. In this talk, I show that, as a
consequence of the rotation of the Earth that breaks time reversal
symmetry, equatorial Kelvin and Yanai waves emerge as topologically
protected edge modes. The non-trivial topology of the bulk Poincaré waves
is revealed through their winding number in frequency – wavevector space.
Bulk-interface correspondence then guarantees the existence of the two
equatorial waves. I discuss our recent direct detection of the winding
number in observations of Earth’s stratosphere.
Thus the oceans and atmosphere of Earth naturally share basic physics with
topological insulators. As equatorially trapped Kelvin waves in the Pacific
ocean are an important component of El Niño Southern Oscillation, the
largest climate oscillation on time scales of a few years, topology plays a
surprising role in Earth’s climate system. We also predict that waves of
topological origin will arise in magnetized plasmas. I will describe
experiments that we are conducting at UCLA’s Basic Plasma Science Facility
(BaPSF). The waves may also arise in the solar system and beyond.

主講者：美國物理學會(APS)主席 Brad Marston 教授

時間：6/23(二) 14:00

地點：科學三館 SC353

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